Study on the speciation of heavy metals in the sediments of the western Arctic Ocean
Bibliographic record
Abstract
The particular behavior of trace metals in the environment is determined by their existing states rather than by their total concentration.In order to evaluate the behavior of Cr,Cu and Pb in the western Arctic Ocean,32 surface sediments were selected from the Chukchi Sea,the Beaufort Sea,and the Canada Basin during the First and Second Chinese Arctic research expedition.The study shows that existing states of heavy metals were divided into exchangeable and carbonate form(P1-2),Fe-Mn oxidation form(or Reducible state,P3),organic matter and sulfide form(or Oxidizable state,P4) and residual form(or Silicate state,P5).The Cr,Cu and Pb contents in bulk sample and four states were determined by sequential extraction method.The results demonstrate that Cr,Cu,Pb contents display an upward tendency with the increasing of both the offshore distance and the water depth.In the study area,Cr,Cu and Pb contents are 60.66,14.77,16.65 μg/g in the shelf sediments,while 80.40,41.70,25.62 μg/g in the deep-sea sediments.The analyses of element speciation show that Cr,Cu,Pb mainly exist in residual form,and the average contents of the three elements are 64.97,19.67,17.56 μg/g which account for 93.58%,75.02% and 83.76% of the total elements respectively.Meanwhile Cr,Cu and Pb content in exchangeable and carbonate form is the lowest of all.Their proportions are all lower than 3%.The distributions of the three elements in each speciation are:Cu in residual form(75.02%) organic matter and sulfide form(14.16%) Fe-Mn oxidation form(10%) exchangeable and carbonate form(0.82%);Pb and Cr in residual form(Pb:83.76%;Cr:93.58%) Fe-Mn oxidation form(Pb:12.24%;Cr:3.65%) organic matter and sulfide form(Pb:3.61%;Cr:2.67%) exchangeable and carbonate form(Pb:2.73%;Cr:0.1%).Speciation distribution of heavy metals in the study area is very similar to that in the deep-sea sediments in the North Pacific.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".